/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package a.gui.proguard.gui.splash;

import java.awt.*;

/**
 * This Sprite adds a drop shadow to another Sprite.
 *
 * @author Eric Lafortune
 */
public class ShadowedSprite implements Sprite {
    private final VariableInt xOffset;
    private final VariableInt yOffset;
    private final VariableDouble alpha;
    private final VariableInt blur;
    private final Sprite sprite;

    private float cachedAlpha = -1.0f;
    private Color cachedColor;

    /**
     * Creates a new ShadowedSprite.
     * 
     * @param xOffset the variable x-offset of the shadow, relative to the sprite itself.
     * @param yOffset the variable y-offset of the shadow, relative to the sprite itself.
     * @param alpha the variable darkness of the shadow (between 0 and 1).
     * @param blur the variable blur of the shadow (0 for sharp shadows, 1 or more for increasingly blurry shadows).
     * @param sprite the Sprite to be painted with its shadow.
     */
    public ShadowedSprite(VariableInt xOffset, VariableInt yOffset, VariableDouble alpha, VariableInt blur,
        Sprite sprite) {
        this.xOffset = xOffset;
        this.yOffset = yOffset;
        this.alpha = alpha;
        this.blur = blur;
        this.sprite = sprite;
    }

    // Implementation for Sprite.

    public void paint(Graphics graphics, long time) {
        double l = alpha.getDouble(time);
        int b = blur.getInt(time) + 1;

        float a = 1.0f - (float)Math.pow(1.0 - l, 1.0 / (b * b));
        if (a != cachedAlpha) {
            cachedAlpha = a;
            cachedColor = new Color(0f, 0f, 0f, a);
        }

        // Set up the shadow graphics.
        // OverrideGraphics2D g = new OverrideGraphics2D((Graphics2D)graphics);
        // g.setOverrideColor(cachedColor);

        // Set the shadow color.
        Color actualColor = graphics.getColor();
        graphics.setColor(cachedColor);

        int xo = xOffset.getInt(time) - b / 2;
        int yo = yOffset.getInt(time) - b / 2;

        // Draw the sprite's shadow.
        for (int x = 0; x < b; x++) {
            for (int y = 0; y < b; y++) {
                int xt = xo + x;
                int yt = yo + y;
                graphics.translate(xt, yt);
                sprite.paint(graphics, time);
                graphics.translate(-xt, -yt);
            }
        }

        // Restore the actual sprite color.
        graphics.setColor(actualColor);

        // Draw the sprite itself in the ordinary graphics.
        sprite.paint(graphics, time);
    }
}
